Instrument for drawing ellipses



March 9 1926. 1,575,889

, P. ZULIANI INSTRUMENT FOR DRAWING ELLIPSES Filed May 21, 192 3 Patented Mar. 9, 1926.

'PATEN T OFFICE.

PIETRO ZULIANI, OF LONATQ, ITALY.

INSTRUMENT FOR DRAWING ELLIPSES.

Application filed May 21,

To all whom it may concern:

Be it known that I, PIETRO ZULIANI, engineer, citizen of the Kingdom of Italy, re-

, siding at Lonato, Cenedella No. 157, in the Province of Brescia, Italy, have invented certain new and useful Improvements in and Relating to an Instrument for Drawing Ellipscs, of which the following is a specification. 7

This invention relates to an instrument for drawing ellipses and similar curves as projection of a circle or parts thereof.

The object of the invention is to provide an instrument of the character describedwhich is simple and economical in construction and particularly adapted to draw ,ellipses or oval curves when the two axis of said curves are given.

The invention consists broadly in-an em--* bodiment of-a frame revolving upon-a spin dle, the latter having adjustable thereon a guide which is formed of two independent semi-circular plates mounted upon a'common axis and against which a bar pivotally connected at the lower end of the frame is adapted to bear, said bar being maintained constantly in such a position by a second bar under resilient tension and which is pro-' vided at its lower end with a suitable drawing pen or the like, this last said bar being pivotally connected to the upper portion of said frame.

The invention will be fully described with reference to the annexed drawing, in which Figure 1 is a side view of the instrument, and

Figure 2 is a view at right angles to that of Figure 1. I

Referring to the accompanying drawing in detail, wherein like reference characters denote corresponding parts throughout the several views, the instrument consists of a frame 1 formed of suitable tubing and provided with an upper curved portion which terminates into a horizontally disposed portion 2 and a downwardly projecting leg 3.

The frame 1, thus described, has passing through the leg 3 a spindle 4 upon which the frame 1 is mounted for rotary movement, the latter being provided with a suitable bearing 6 and 7 at the upper and lower portions of the le 3. The upper end portion of the spindle ears upon a bearing block 5 mounted within the horizontally disposed. portion 2. The lower end portion of the 192s. sem No. 640,525.

spindle 4 is pivotally connected to a foot piece 8, the same having points 9 for maintaining the instrument in a desired point when using.

Mounted upon the spindle-4 is a guide element formed'of a pair of semi-circular plates 10 connected together upon a common axis, the intermediate portion of which is,.provided with a suitable opening through which the spindle passes. The plates 10 have pivotally connected thereto arms 12 which are further pivotally connected to a sliding piece 11 mounted upon the spindle 4 and maintained -in a desired position by a thumb screw 13. From this construction it will be noted that as the sliding piece 11 is moved with respect to the axis. of the plates 10 their inclination will be accordingly changed. The plates 10 are further provided with extensions 1 1 the end portions of each'pair having passing therethrough the ends of pins 22'. carried by a .block23 adjustable edge of the plates 10 in a manner hereinafter described. The bar 19 is provided with an elongated slot 19, the purpose of which will hereinaften be described.

The horizontally disposed portion 2, of the frame 1, has pivotally connected to its end a bar 15 which does not, fall within the same vertical plane with the bar 19. As disclosed in the drawing it will be noted that the bar 15 is caused to swing inward toward the base 8 by a suitable tension spring 16, one end of which is connected to the frame portion 2 while the other end is connected to the bar 15.

In order to maintain the bar 15 in such a position that it will be acted upon by the bar 19, as the latter follows the periphery of the plates 10, I have provided upon the bar 15 a sliding piece 17 which carries a projection18 adapted to be received within the slot 19 of the bar 19, the sliding piece 17 being adjustable upon the bar'15 and secured in a desired point by a thumb screw 20. with a suitable scribing element 21.

The lower end of the bar 15 is provided on the given center of the curve. Then turn the frame by means of the-finger piece 22 until the axis of the split guide plate falls within a plane common to that of the upper portion of the frame. The sliding piece 17 is next adjusted to make theend of the pen 21 coincide with the end of the longer axis of the curve, and the frame is then turned 90 to bring the plane of the frame in such a position that the end of the pen will be on the minor axis of the curve. The operator then adjusts the sliding piece 11 to bring the end of the pen coincident with the end of theminor axis.

The instrument as thus described is prepared to draw the desirable curve, which will be traced as it is done with the ordinary compass.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is

1. An instrument of the class described'ineluding a spindle, a frame pivoted to and.

movable about said spindle and having a marking element connected thereto, a pair of semi-circular plates, means pivoting said plates on a common axis, said means having therein an opening through which the spindle passes, means connected to said lates andslidable upon said spindle wherey'said plates are adapted to assume various angles of inclination, a bar connected to said frame and means for resiliently holding said bar against the peripher of said plates during the movement of the rame about the spindle, saidbar being adapted to control the movement of said marking element.

2. An instrument of the class described including a spindle, a frame pivoted to and rotatable upon, said spindle, a marking element pivotally connected to said frame, a pair of semi-circular plates,means pivoting said plates on a common axis, said means having the spindle passing therethrough, means connected to said plates and slidable upon said spindle for moving the plates into various angles of inclination, a bar movable -Wll3h respect to said frame and means for holding the same against the periphery of said plates when moved thereabout, said bar being adapted to controlthe movement of said marking element when the frame ismoved about the s indle.

In testimony w ereof I affixed my signature.-

PIETRO ZULIANI. I 

